J 56 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL 



space between them gradually increases from A' to the lower point h^ ; (the 

 shaft D, passes through steam tight stuffing boxes in the cylinder ends, and 

 revolves in bearings on the frames Z Z. which are firmly bolted to the found- 

 ation plate, and stayed to the cylinder.) E E. are two sliding pistons, con- 

 sisting each of two arms, connected together by four rods passing over the 

 shaft, their breadth is equal to that of Ihe outer cylinder, and their joint 

 Icnglh over their extremeties is necessarily somewhat less than its diameter, 

 owing to the eccentricity of the revolving cylinder ; these pistons slide freely 

 at right angles to one another, through passages made in the circumference 

 of the revolving cylinder, their sliding motion being caused by Ihe pressure 

 of one of their extremities on the ascending side cf the outer cylinder, (which- 

 ever side that may be,) and the eccentricity of the revolving cylinder through 

 ■which they slide; as their length is always slightly varying during the 

 course of a revolution, the difference is made up by metallic packing placed 

 between the two thicknesses of plates, of which the arms of the pistons are 

 composed, the packing is pressed by springs towards the sides and circum- 

 ference of the outer cylinder, and will be understood by referring to Figures 

 1 and 2 on the drawing. There are metallic packings, (in the passages in the 

 inner cylinder, through which the pistons slide,) which are pressed on the 

 flat surfaces of the pistons by sprines. and prevent the steam passing to the 

 interior. There are a'so two steel rollers at the inside of the packings, which 

 are pressed up to the flat sides of the pistons by screws; these are for the pur- 

 pose of diminishing the friction of their sliJi'g motion. These rrdlers would 

 not be necessary excepting in large engines. The rim of the inner cylinder is 

 made lo project into metallic packing boxes in the cylinder ends, thus the 

 steam is enlirely prevented from passing into the interior of the inner cylin- 

 der ; a packing box is also placed at the point of contact A> to prevent the 

 steam passing to either side. It will theref Te be understood, that the steam 

 onlv acts on the projecting part of the sliding pistons, between the inner 

 and outer cylinders. 



The steam in coming from the boiler through the steam pipe F, has first 

 to pass the slide G, which is worked by the handle H; it is used for regulating 

 the speed of the engine, and also for stoppingit, when required : after passing 

 the above slide it enters the steam tight jacket J, the bottom of which is the 

 slide face having the four cylinder ports K, L, M and N, and the eduction 

 port Q, on it; a slide O, worked by a handle P, passes over these ports lor 

 the purpose of reversing the motion of the engine: there are two posts 

 0' and 02. on the slide, one of which, 0^', (in the position the slide is shown 

 on the drawing) is open to the steam port L; the port N, is closed, and the 

 two ports M and K. are op n to the eduction port Q. so that when the slide 

 is in this position, the engine will necessarily move in the diiection indicated 

 by the arrov^■s, and by moving the slide along until the port 0' is above the 

 steam port K, then will the port M, be closed, and N and L. open to eduction, 

 so that the steam will act at the opposite side of the cylinder and conse- 

 quently the motion be reversed. 



It will here be observed that the lower cylinder ports M and N, are never 

 used for admitting steam, but only for leading off the eduction ; the object 

 in placing them so low in the cylinder is to allow the vacuum to act upon 

 the pistons sooner ; it will be kept in mind then that, in whatever direction 

 the shaft revolves, the steam is always .admitted at one of the upper ports 

 K or L, and the eduction Ipd off at iis opposite lower and upper ports. All 

 these ports where they lead into the cylinder, are divided into bridges placed 

 diagonally across them so that the pistons may pass freely over them. 



From the relative position of the two cylinders, the distance between their 

 circumferences gradually increasing from contact at the upper point /i', to 

 the greatest distance at the lower point h", (which in this case is one-sixth 

 of the diameter of the external cylinder, but may be varied according to cir- 

 cumstances,) it will be seen that in whatever direction the engine revolves, 

 the area of that part of the pistons which is acted on by steam and vacuum 

 gradually increases, so that the principle of expansion is carried out to its 

 fullest extent, without the aid of expansion valves and gear. 



The steam passing through the eduction passage Q, is conducted by the 

 eduction pipe R, to the condenser S ; T, is the inspection slide, placed at 

 the lower end of the eduction pipe, and conducting the water up Ihe pipe, so 

 as to act fully on the steam in passing downwards: it is worked by a lever 

 and rod connected to the handle U, which is placed in proximity with the 

 other starting handles H and P. V, is the blow through valve. W, is the 

 air pump, which is a double acting one, the interior arrangement of its valves 

 &c., is shown at Fig. 1 ; it has a metallic packed piston which is worked 

 from the main shaft by a crank and connecting rod, and the piston rod is. 

 kept parallel by two slide guides bolted on the air pump cover. X, is the hot 

 well, and Y, the discharge passage. 



The pumps are worked from the main shaft by an eccentric c, connected 

 by rod and lever to a rocking shaft d, on wliich are keyed two levers, e and /, 

 which are connected by rods to the pumps, g and h • the pumpg, is intended 

 for the bilge water (supposing this to he a marine engine), and the pump h, 

 for feeding the boilers, the latter has its valve chest 7, bolted on the hot well. 

 Among the advantages which render this improved steam engine 50 pecu- 



imOiBH 



liarly well adapted for locomotive and marine purposes, may be mentioned 

 the following, viz. ; — Small cost of construction, great economy of fuel, the 

 space occupied by it is very little in proportion to its power, and also its com- 

 parative lightness, the weight of the engine being only about 2 cwt., per horse 

 power, and that of the boilers only about 21 cwt. per horse power, so that 

 the whole weight will only be about one half of the lightest engine hitherto 

 constructed. 



I herewith annex the following analysis of the power and economy of my 

 " Patent Revolving Steam Engine." 



In the above figure, 3, the revolution of one piston is divided into 32 equal 

 parts, and the annexed table shows the quantity of steam consumed ; the 

 mean area of the piston, the distance the centre of pressure of the piston 

 travels; the direel, opposite, and effective pressures on the piston ; the num- 

 ber of times to which the steam is expanded ;and the number of llis. lifted one 

 foot high in passing through each of these divisions. Tlie external cylinder 

 is 3 ft. 6 in. diameter, and 1 it. 6 in. long inside, and the greatest distance be- 

 tween it and the intf inal cylinder, is 7 in. The steam is supposed to be at a 

 pressure of 30 lb. on the square inch, above the atmosphere, and the vacuum to 

 be equal to 121b. on the square inch, the shaft making 50 revolutions per 

 minute. 



Note.— The direct pressure or force of the steam lo turn the engine round 

 in the required diiection, is marked on the Table, + pressure, and thi opposite 

 ir force resisting the motion in that direction, — pressure, of course, their 

 diHerence, is the elfective pressure. 



* [We are indebted to our contemporary, the "Mccliauics' Magazine," for tlie use of 

 tlje wood engravings.] 



